|Yakult, A drink containing Lactobacillus casei|
Hansen & Lessel 1971
Lactobacillus casei is a species of genus Lactobacillus found in the human intestine and mouth. This particular species of Lactobacillus is documented to have a wide pH and temperature range, and complements the growth of L. acidophilus, a producer of the enzyme amylase (a carbohydrate-digesting enzyme).
Lactobacillus casei is considered a probiotic safe for consumption.
Dairy production 
The most common application of L. casei is industrial, specifically for dairy production. However, a team of scientists from Simón Bolívar University in Caracas, Venezuela found that, by using L. casei bacteria in the natural fermentation of beans, the beans contained lower levels of the compounds causing flatulence upon digestion.
Lactobacillus casei is typically the dominant species of nonstarter lactic acid bacteria (NSLAB) present in ripening Cheddar cheese, and, recently, the complete genome sequence of L. casei ATCC 334 has become available. L. casei is also the dominant species in naturally fermented Sicilian green olives.
A commercial beverage containing L. casei strain Shirota has been shown to inhibit the growth of Helicobacter pylori in vivo. But, when the same beverage was consumed by humans in a small trial, H. pylori colonization decreased only slightly, and the trend was not statistically significant. Some L. casei strains are considered to be probiotic, and may be effective in alleviation of gastrointestinal pathogenic bacterial diseases. According to World Health Organization, those properties have to be demonstrated on each specific strain—including human clinical studies—to be valid. L. casei has been combined with other probiotic strains of bacteria in randomized trials studying its effects in preventing Antibiotic associated diarrhea (AAD) and Clostridium difficile infections (CDI) and patients in the trials who were not given the placebo had significantly lower rates of AAD or CDI (depending on the trial) with no adverse effects reported. Additionally, trials have shown significantly shorter recovery times in children suffering from acute diarrhea (primarily caused by rotavirus) when given different L. casei treatments when compared to placebo. Studies suggest that Lactobacillus is a safe and effective treatment for acute and infectious diarrhea.
Commercial probiotic 
Among the best-documented, probiotics L.casei, L. casei DN-114001, and L. casei Shirota have been extensively studied and are widely available as BIO-K Plus functional foods (see Actimel, Yakult). In India, yogurt which has the same benefits is consumed as a food (see Amul Yoghurt).
In the past few years, there have been many studies in the decolorization of azo dyes by lactic acid bacteria such as L. casei TISTR 1500, L. paracasei, Oenococcus oeni. With the azoreductase activity, mono-, di- azo bonds are degraded completely, and generate other aromatic compounds as intermediates.
See also 
- Bio-k Plus
- Actimel yoghurt, called DanActive in some markets
- Prebiotic (nutrition)
- Lactic acid bacteria
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- "Joint FAO/WHO Working Group Report on Drafting Guidelines for the Evaluation of Probiotics in Food". London, Ontario, Canada. April 30 and May 1, 2002.
- McFarland, LV (2009). "Evidence-based review of probiotics for antibiotic-associated diarrhea and Clostridium difficile infections.". Anaerobe 15 (6): 274–80. doi:10.1016/j.anaerobe.2009.09.002. Retrieved 2012-04-15.
- Isolauri, Erika; et al. (1991). "A Human Lactobacillus Strain (Lactobacillus Casei sp strain GG) Promotes Recovery From Acute Diarrhea in Children". Pediatrics 88 (1): 90–97. Retrieved 2012-04-15.
- "Lactobacillus Therapy for Acute Infectious Diarrhea in Children: A Meta-analysis". Pediatrics 109 (4): 678–684. 2002. doi:10.1542/peds.109.4.678.
- Kazuyoshi Takeda and Ko Okumura. "Effects of a Fermented Milk Drink Containing Lactobacillus casei Strain Shirota on the Human NK-Cell Activity".
- Seesuriyachan P, Takenaka S, Kuntiya A, Klayraung S, Murakami S, Aoki K (March 2007). "Metabolism of azo dyes by Lactobacillus casei TISTR 1500 and effects of various factors on decolorization". Water Res. 41 (5): 985–92. doi:10.1016/j.watres.2006.12.001. PMID 17254626.